Extension head for lifting jacks



Jmzs, ma. F AGRAHAM A 1029,@22

EXTENSION HEAD FOR LIFTING JACKS Filed Nov. 16, 1934 Patented Jan. 28,1936 UN'EE STA-.TES

BA'EENT GFFIQE EXTENSION HEAD Fon LIFTING .mons

Application November 16, 1934, Serial No. 753,278

6 Claims. The present invention relates to lifting jacks and has for anobject to provide a novel means for quickly adapting the jack for workat diiferent heights.

The invention is especially (although not exclusively) adapted for useon automobile `iacks. The axles of modern cars are much lower than thoseof older models and in order to provide a jack which may be adjustedinstantly for low N axled or high aXled cars, I have devised a headwhich may be readily raised or lowered with respect to the normallifting mechanism of the jack.

A more speciiic object of the invention is to 3;, provide a headcomprising a bearing member and a rest plate removably mounted therein,the parts being so constructed and arranged that when the rest plate isapplied in one way it will occupy a higher position with respect to thebearing mem- 20 ber than when applied in another way. By thisarrangement the rest plate may be normally adapted for use with lowaXled cars, but whenever a high axled car is to be jacked up the restplate is lifted off its bearing and reapplied thereto in such a way asto occupy its higher position. With the above-named objects in View andothers which will appear hereinafter I shall now describe a preferredembodiment of my invention and thereafter the novelty and scope of the30 invention will be pointed out in the claims.

In the accompanying drawing: Figure l is a View in perspective of a jackembodying my improved extension head;

Fig. 2 is a view in section, but on a larger scale, 35 taken on line 2-2of Fig. 1, and showing the extension head in raised position;

Fig. 3 is a View in section taken on line 3 3 of Fig. 2; and,

Fig. 4 is aview in section, taken on line 4 6 l0 of Fig. 2, but with thehead in lowered position. It will be understood that my extension headmay be applied to different forms of jacks and that I make no claim tothe particular jack illustrated in Fig. 1. The novelty lies in theexten- 45 sion head applied thereto.

The jack I has an extension head comprising a bearing member I I whichis pivoted to the lifting armV i2 of the jack and is maintained invertical position by parallel links I3. The bearing member is formedwith a vertical bore I5 adapted to receive the stem I6 oi a rest plateIl. The bore E5 has a pair of diametrically opposed key slots I8 cuttherein and extending the full length of the bore. It also has anotherpair of diametrically opposed key slots i9 cut therein and extendingfrom the top of the bore to 'a point part way down where they terminatein end walls 2Q. The pairs of slots are disposed at 90 degrees to eachother. The stem i6 is provided lwith a pair of diametrically opposedkeys ZI which are adapt- 5 ed to t into either pair of key slots.

Normally, the rest plate is in its lowermost position which means thatthe stem has been turned to such position that the keys 2! nt in thekeyways I 8. This permits the rest plate to drop until a shoulder 23 onthe lower side thereof bears against the upper end of the bearing memberII. However, if it be desired to adjust the jack quickly for use with ahigh axled car, it is merely necessary to lift the head from theposition shown in Fig. 4 out of the bearing member and then afterturning it through an angle of 90 degrees reinsert the stem in thebearing member with the keys now tting in the keyways I9. The

rest plate will now occupy the position shown in Fig. 2 with the lowerends of the keys resting on the shoulders or walls 2li at the lower endsof the slots I9.

The rest plate is preferably formed as illustrated with a dished uppersurface having a marg5 ginal rim. This rim is depressed to form twopairs of diametrically opposed sockets or seats 22 adapted to receivethe axle of the car. The axes of these seats are disposed at 90 degreesto each other so that in either angular position of the rest plate therewill be a pair of seats in Y proper position to support a car axletransversely with respect to the jack.

Having thus described my invention what I claim as new and on which Idesire to secure Letters Patent is as follows:

I claim:

i. A head for a lifting jack comprising, a bearing member, a rest platemember constructed and arranged to be removably supported on the bearingmember in either of two positions angularly disposed one to the other,said members being provided with cooperating means to support the restplate against angular movement and to maintain the rest plate at amaterially higher level when applied to the bearing member in one ofsaid positions than when applied to the bearing member in the other.

2. A head for a lifting jack comprising, a bearing member, a rest platemember constructed and arranged to be removably supported by the bearingmember in either of two positions disposed at 90 degrees to each other,said members being provided with cooperating means for preventing therest plate member from turning with 55 and arranged to be removablysupported on the bearing member in either of two positions angularlydisposed one to the other, one of said members having a bore, the otherof said members having a stem adapted to t in the bore, the stem andbore being provided with keys and keywa-ys certain of which are inmutual engagement when the stem is introduced into the bore in oneposition and others of which are in mutual engagement and cooperate tosupport the rest plate at a higher level when the stem is introducedinto the bore in a different angular position.

4. A head for a lifting jack comprising, a bearing member formed with avertical bore, and a Yrest plate formed with a stem adapted to fitslidably within said bore, said stem being formed with a pair ofdiametrically opposed keys and said bore being formed with two pairs ofdiametrically opposed key slots adapted to receive said keys, one pairof key slots being marially shorter than the other.

5. A head for a lifting jack comprising, a bearing member formed vwitharvertical bore, and a rest plate formed with a stem adapted to fitslidably Within said bore, said stem being formed with a pair ofdiametrically opposed keys and said bore being formed with two pairs ofdiametrcally opposed key slots adapted to receive said keys, one pair ofkey slots being'disposed at 90 degrees to the other and also extendingthe full length of the bore while said other pair ofV key slots extendsfrom the top, of the bore to a point intermediate the ends Vofthe bore.

6, A head for a lifting jack comprising, a bearing member formed with avertical bore, and a restplate formed with a stem adapted to fit slid'rably within said bore, said stem being formed with a pair ofdiametrically opposed keys and said bore being formed with two pairsofdiametrically opposed key slots adapted to receive said keys, one pairof key slots being disposed at 90 degrees to the other and alsoextending Vthe full length of the bore while said other pair of keyslots extends from the top of the bore to a point intermediate-the endsof the bore, the rest plate having work-receiving depressions on axes at90 degrees to each other.

FRANK A. GRAHAM.

